/Engine/Plugins/Experimental/PCG/Source/PCG/Public/Elements/Metadata/PCGMetadataOpElementBase.h
Finally we call our callback with the packed input values from InArgs, and set the output value in its accessor. We use OutputIndex to know which callback to get (and therefore which output to set). Note that we go in reverse order, and stop when OutputIndex is negative.
namespace PCG { namespace Private { namespace NAryOperation { template<int OutputIndex, typename... Callbacks, typename... Args> bool PCG::Private::NAryOperation::Apply ( [FPCGMetadataElementBase::FOperationData](API\Plugins\PCG\Elements\Metadata\FPCGMetadataElementBase\FOperationData) & InOperationData, int32 StartIndex, int32 Range, const [Options](API\Plugins\PCG\Elements\Metadata\Options) & InOptions, const [TTuple](API\Runtime\Core\Misc\TTuple)< Callbacks... > & InCallbacks, Args &&... InArgs ) } } }